Sheet type discrimination device and sheet type discrimination device control program

ABSTRACT

A sheet type discrimination device includes a holder that holds a sheet, a conveyor that conveys a sheet from the holder along a conveyance path, a measurer that measures a basis weight of the sheet conveyed along the conveyance path, a storage that stores a type discrimination table describing a relationship between the basis weight and a type of a sheet, and a hardware processor that sets the type of the sheet held in the holder on the basis of the basis weight measured by the measurer.

The entire disclosure of Japanese patent Application No. 2018-204346,filed on Oct. 30, 2018, is incorporated herein by reference in itsentirety.

BACKGROUND Technological Field

The present invention relates to a sheet type discrimination device anda sheet type discrimination device control program. The presentinvention more particularly relates to a sheet type discriminationdevice and a sheet type discrimination device control program capable ofsuppressing an increase in time taken for printing.

Description of the Related Art

An electrophotographic image forming apparatus includes: a multifunction peripheral (MFP) having a seamier function, a facsimilefunction, a copying function, a printer function, a data communicationfunction, and a server function; a facsimile machine; a copying machine;and a printer.

When performing printing, the image forming apparatus sets parameterssuch as the conveyance speed to appropriate values in accordance withthe sheet type to enhance image quality and avoid occurrence of problemssuch as jams. Therefore, in order to enable the image forming apparatusto appropriately execute printing, the type of sheet held in the sheetfeed tray needs to be set correctly.

Unfortunately, however, it is difficult for the user to accuratelydetermine the type of sheet, and this, the type of sheet might beerroneously set when the sheet is held in the sheet feed tray, leadingto a problem such as jam. To handle this, a conventional image formingapparatus measures the basis weight of the sheet on the basis of thereflected light amount and the transmitted light amount of the sheet,and then uses a sheet type discrimination table preliminarily stored inthe storage to determine the sheet type on the basis of the measuredbasis weight. This type of image forming apparatus performs printing ona sheet while conveying the sheet at a conveyance speed corresponding tothe discriminated type. The sheet type discrimination table includes therelationship between the sheet type and the basis weight range.

Techniques related to sheet type discrimination are disclosed in JP2017-193390 A, JP 2005-062916 A, JP 2001-213032 A, or the like. JP2017-193390 A discloses a technique of detecting a thickness indexvalue, which is an index value of the thickness of a sheet using acentral region located at the center in a width direction of the sheetand a first end region and a second end region located at both outersides in the width direction of the sheet than the central area, asdetection positions.

JP 2005-062916 A discloses a technique of judging whether the sheet typeset in the printer is incompatible with the sheet set by a print settingprocessing part and restricting print data generation by a print datageneration processing part or output of the generated print data.

JP 2001-213032 A discloses a technique of acquiring, by a printer driverof a host apparatus, ink characteristic information stored in an inkcartridge from the printer and determining the type of sheet on whichprinting can be performed by the ink cartridge mounted on the printerfrom the acquired ink characteristic information. The printer driversets a sheet selection menu presenting the defined sheet type selectableby the user and displays the sheet selection menu on a setting screen.

In a case, on the conventional sheet type discrimination table, where afirst range which is a range of a basis weight of a first type of sheethaving a high conveyance speed and a second range which is a range of abasis weight of a second type of sheet having a low conveyance speed areprescribed adjacent to each other and when the measured basis weight isa value within the second range, the sheet is discriminated to be thesheet of the second type having a low conveyance speed.

Meanwhile, high image quality is preferably achieved at the time ofprinting a photographic image. Accordingly, when printing a high qualityimage such as a photographic image on a sheet there is a need todecrease the sheet conveyance speed. In contrast, the image qualitypreferable at the time of printing a document or the like may generallybe lower than the image quality required for a photo. Accordingly, whenprinting a document, it is possible to print an image of sufficientquality even at a high conveyance speed.

The basis weight range prescribed in the conventional sheet typediscrimination table has been a range that achieves a conveyance speedthat would not cause a problem in the image quality regardless of therequired image quality in a case where the sheet having the basis weightwithin the range is conveyed. Therefore, when the measured basis weightis a value within the second range, being a value near the boundaryvalue between the first range and the second range, the sheet would beconveyed at a slow conveyance speed even when it is possible, inprinting a document or the like, to print an image with sufficientquality even at a high conveyance speed, and this has increased time forprinting.

SUMMARY

The present invention is made in view of the above problem, and aims toprovide a sheet type discrimination device and a sheet typediscrimination device control program capable of suppressing an increasein time for printing.

To achieve the abovementioned object according to an aspect of thepresent invention, a sheet type discrimination device reflecting oneaspect of the present invention comprises a holder that holds a sheet, aconveyor that conveys a sheet from the holder along a conveyance path, ameasurer that measures a basis weight of the sheet conveyed along theconveyance path, a storage that stores a type discrimination tabledescribing a relationship between the basis weight and a type of asheet, and a hardware processor that sets the type of the sheet held inthe holder on the basis of the basis weight measured by the measurer,wherein the type discrimination table prescribes a unique range being arange of basis weight in which the sheet type is uniquely discriminated,and a selection range being a range of basis weight in which the sheettype is discriminated into either of a first type in which the basisweight is relatively large and a second type in which the basis weightis relatively small, the sheet type discrimination device furthercomprising a selection screen display that displays a selection screenbeing a screen that receives operation of selecting the sheet type fromthe first and second types in a case where the basis weight measured bythe measurer is within the selection range, and that receives selectionthrough the selection screen, and in a case where the selection screenis displayed, the hardware processor sets the type of the sheet field inthe holder to the type received through the selection screen.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features provided by one or more embodiments of theinvention will become more fully understood from the detaileddescription given hereinbelow and the appended drawings which are givenby way of illustration only, and thus are not intended as a definitionof the limits of the present invention:

FIG. 1 is a front view illustrating an external configuration of animage forming apparatus according to a first embodiment of the presentinvention;

FIG. 2 is a cross-sectional view schematically illustrating aconfiguration of the image forming apparatus according to the firstembodiment of the present invention;

FIG. 3 is a block diagram illustrating a configuration of the imageforming apparatus according to the first embodiment of the presentinvention;

FIG. 4 is a view schematically illustrating a sheet feed trayinformation table stored in a storage in the first embodiment of thepresent invention;

FIG. 5 is a view schematically illustrating a first setting screen ofsheet feed tray information displayed on an operation panel in the firstembodiment of the present invention;

FIG. 6 is a view schematically illustrating a second setting screen ofthe sheet feed tray information displayed on the operation panel in thefirst embodiment of the present invention;

FIG. 7 is a view schematically illustrating a conventional sheet typediscrimination table;

FIG. 8 is a view schematically illustrating an example of a sheet typediscrimination table stored in the storage in the first embodiment ofthe present invention;

FIG. 9 is a view schematically illustrating a selection screen to bedisplayed on the operation panel in a case where the basis weighmeasured by a basis weigh sensor is a value within a selection range of“85 g/m² to 94 g/m²” in the first embodiment of the present invention;

FIG. 10 is a view schematically illustrating another example of a sheettype discrimination table stored in the storage in the first embodimentof the present invention;

FIG. 11 is a view schematically illustrating a second setting screen ina case where the setting of the sheet type is received through thesecond setting screen after setting is performed to the sheet typeselected on the selection screen in the first embodiment of the presentinvention;

FIG. 12 is a flowchart illustrating operation of the image formingapparatus according to the first embodiment of the present invention;

FIG. 13 is a flowchart illustrating operation of the image formingapparatus according to a second embodiment of the present invention;

FIG. 14 is a subroutine of selection necessity determination processing(S21) in the first example of the second embodiment of the presentinvention;

FIG. 15 is a view schematically illustrating a conveyance speeddiscrimination table stored in the storage in the second embodiment ofthe present invention;

FIG. 16 is a view schematically illustrating an image quality-prioritysheet type discrimination table stored in the storage in the secondembodiment of the present invention;

FIG. 17 is a subroutine of selection necessity determination processing(S21) in a second example of the second embodiment of the presentinvention;

FIG. 18 is a subroutine of selection necessity determination processing(S21) in a third example of the second embodiment of the presentinvention;

FIG. 19 is a subroutine of selection necessity determination processing(S21) in a fourth example of the second embodiment of the presentinvention;

FIG. 20 is a flowchart illustrating setting change processing performedby the image forming apparatus in a first example of a third embodimentof the present invention;

FIG. 21 is a flowchart illustrating setting change processing performedby the image forming apparatus in a second example of the thirdembodiment of the present invention;

FIG. 22 is a flowchart illustrating setting change processing performedby the image forming apparatus in a third example of the thirdembodiment of the present invention; and

FIG. 23 is a flowchart illustrating setting change processing performedby the image forming apparatus in a fourth example of the thirdembodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, one or more embodiments of the present invention will bedescribed with reference to the drawings. However, the scope of theinvention is not limited to the disclosed embodiments.

The following embodiments describe a case where a sheet typediscrimination device is mounted on an image forming apparatus. Examplesof the image forming apparatus include an MFP, a printer, a copyingmachine, and a facsimile. The sheet type discrimination device may alsobe mounted on a device such as a sheet storage or a post-processingdevice other than an image forming apparatus.

First Embodiment

<Configuration of Image Forming Apparatus>

FIG. 1 is a front view illustrating an external configuration of animage forming apparatus 1 according to a first embodiment of the presentinvention. FIG. 2 is a cross-sectional view schematically illustrating aconfiguration of the image forming apparatus 1 according to the firstembodiment of the present invention.

Referring to FIGS. 1 and 2, the image forming apparatus 1 (example of asheet type discrimination device) according to the present embodimentincludes: a sheet conveyor 10 (example of a conveyor); a toner imageformer 20 (example of an image former); a fixing device 21; an operationpanel 22 (example of a selection screen display, a setting screendisplay, and another selection screen display); and a basis weightsensor 23 (example of a measurer).

The sheet conveyor 10 conveys a sheet from one of the plurality of sheetfeed trays 11 or a manual feed tray 12, along a conveyance path TR. Thesheet conveyor 10 includes: the plurality of sheet feed trays 11(example of a holder); the manual feed tray 12 (example of a holder);sheet feed rollers 13 and 14; a registration roller 15; a sheetdischarge roller 16; and a sheet discharge tray 17. The plurality ofsheet feed trays 11 each holds sheets on which an image is to be formed.The manual feed tray 12 holds sheets for manual feeding. The sheet feedroller 13 is provided between the sheet feed tray 11 and the conveyancepath TR, and feeds sheets held in the sheet feed tray 11 one sheet at atime. The sheet feed roller 14 is provided between the manual feed tray12 and the conveyance path TR, and feeds sheets held in the manual feedtray 12 one sheet at a time. The registration roller 15 is providedupstream of the conveyance path TR with respect to a transfer positionST by the toner image former 20. The sheet discharge roller 16 isprovided at the most downstream portion of the conveyance path TR. Thesheet discharge tray 17 is provided at the uppermost portion of an imageforming apparatus main body 1 a.

The toner image former 20 forms an image on a sheet in accordance with ajob received by the image forming apparatus 1. The toner image former 20combines images of four colors of yellow (Y), magenta (M), cyan (C), andblack (K) by a tandem system to form a toner image on the conveyed sheetat the transfer position ST. The toner image former 20 includes anintermediate transfer belt 20 a. The toner image former 20 also includesa photosensitive drum, a charging roller, an exposure device, adeveloping device, a primary transfer roller, a secondary transferroller, or the like.

The fixing device 21 grips and conveys the sheet carrying a toner imagealong the conveyance path TR so as to fix a toner image onto theconveyed sheet.

The operation panel 22 receives various types of operation related tothe operation of the image forming apparatus 1 and displays varioustypes of information.

The basis weigh sensor 23 measures the basis weight of the sheetconveyed along the conveyance path TR at a detection position on theupstream side of the conveyance path TR relative to the registrationroller 15.

The image forming apparatus 1 feeds sheets held in the sheet feed tray11 or the manual feed tray 12 one at a time to the conveyance path TR bythe sheet feed roller 13 or 14. After temporarily stopping the sheetusing the registration roller 15, the image forming apparatus 1 convey sthe sheet to the transfer position ST in accordance with the tinting oftransfer by the toner image former 20. The image forming apparatus 1uses the basis weight sensor 23 to measure the basis weight of the sheettemporarily stopped by the registration roller 15. The image formingapparatus 1 may measure the basis weight of the sheet being conveyed.

Meanwhile, the image forming apparatus 1 causes the toner image former20 to generate a toner image on the intermediate transfer belt 20 a ofthe toner image former 20 by a known electrophotographic method andtandem method, and conveys the toner image toward the transfer positionST by rotation of the intermediate transfer belt 20 a. A sheet is fedfrom the registration roller 15 a toner image is conveyed from the tonerimage former 20 to the transfer position ST. The image forming apparatus1 transfers the toner image from the intermediate transfer belt 20 a tothe sheet at the transfer position ST.

The image forming apparatus 1 uses the fixing device 21 to heat andpresses the sheet on which the toner image is formed. With thisoperation, the toner image is fixed onto the sheet. Thereafter, theimage forming apparatus 1 discharges the sheet to the sheet dischargetray 17 by the sheet discharge roller 16.

FIG. 3 is a block diagram illustrating a configuration of the imageforming apparatus 1 according to the first embodiment of the presentinvention.

Referring to FIG. 3, the image forming apparatus 1 further includes: asystem controller 101; a memory 103; an input image processing part 104;an imaging part 105; a storage 106 (example of a storage); an outputimage processing part 107; a printer engine 108; a sheet type settingpart 109 (example of a setting part a clanging part, a first settingchanging pan, a second setting changing part, and a third settingchanging part); a network interface 110; an authentication part 111;various sensors 112 (example of a change detector); a positioninformation acquisition part 113 (example of a position acquisitor); anecessity discrimination part 114 (example of a necessity discriminationpart); and an evaluation part 115 (example of an evaluation part).

The system controller 101 includes a central processing unit (CPU) 102and controls the entire image forming apparatus 1. The CPU 102 operatesin accordance with a control program. The system controller 101 isconnected to each of the memory 103, the input image processing part104, the imaging part 105, the storage 106, the output image processingpart 107, the printer engine 108, the sheet type setting part 109, thenetwork interface 110, the authentication part 111, the various sensors112, the position information acquisition part 113, the necessitydiscrimination part 114, and the evaluation part 115.

The memory 103 includes: a read only memory (ROM) that stores a controlprogram, a fixed value, or the like; and a random access memory (RAM)that temporarily stores various types of data such as an image.

The input image processing part 104 processes input image data read bythe imaging part 105.

The imaging part 105 reads an image.

The storage 106 is an auxiliary storage, and stores various types ofdata such as a sheet type discrimination table, a conveyance speeddiscrimination table, and the number of occurrences of jams.

The output image processing part 107 processes image data to createprint data.

The primer engine 108 prints the prim data created by the output imageprocessing part 107 on a sheet.

The sheet type setting part 109 sets the type of sheet held in the sheetfeed tray 11 or the manual feed tray 12 on the basis of the basis weightmeasured by the basis weight sensor 23. In addition, the set sheet typeis changed as necessary.

The network interlace 110 communicates with devices on the network.

The authentication part 111 authenticates a user who uses the imageforming apparatus 1.

Tire various sensors 112 includes: an open/close detection sensor thatdetects opening and closing of each of the plurality of sheet feed trays11; a sheet detection sensor that detects a sheet on the manual feedtray 12; a size detection sensor that detects size and direction of tiresheet held in each of the plurality of sheet feed trays 11 and themanual feed tray 12; a load amount sensor that detects the load amountof sheets stored in each of the plurality of sheet feed trays 11 and themanual feed tray 12; a color detection sensor that detects tire color ofthe sheet being conveyed; and an image density control (IDC) sensor thatdetects density of the toner image formed on the intermediate transferbelt 20 a.

The position information acquisition part 113 acquires positioninformation and entry/exit information of the user of the image formingapparatus 1 from a server of a global positioning system (GPS) or of anentry management system.

The necessity discrimination part 114 discriminates the necessity ofdisplay of a selection screen described below.

The evaluation pan 115 evaluates tire quality of the image formed bytire toner image forming part 20.

(Street Feed Tray Information)

FIG. 4 is a view schematically illustrating a sheet feed trayinformation table stored in the storage 106 in the first embodiment ofthe present invention.

Referring to FIG. 4, the sheet feed tray information table describesinformation (hereinafter, sometimes referred to as sheet feed trayinformation) set for sheets stored in sheet feed tray 11 and the manualfeed tray 12. Here, the sheet feed tray information table describes thesheet feed tray information regarding each of items of size, direction,type, and discrimination operation setting for the sheet held in each ofthe four sheet feed trays 11 (trays 1 to 4) and the manual feed tray 12.

The sheet type setting of tire sheet feed tray information may use tiresetting input by the user through the setting screen (FIGS. 5 and 6)described below, or tire setting determined on the basis of tiremeasurement result obtained by the basis weight sensor 23.

Similarly, the setting of sheet size and direction of the sheet feedtray information may use the setting input by the user through thesetting screen (FIGS. 5 and 6) described below, or the settingdetermined on the basis of the detection result obtained by the varioussensors 112.

The discrimination operation setting includes setting items related tothe timing of performing the sheet type discrimination based on thebasis weight measured by the basis weight sensor 23. The field of thediscrimination operation setting is a field in which one of the “notexecute” which is a setting of not performing discrimination, “execute”which is a setting of performing discrimination every time the sheet isconveyed, and “automatic” which is a setting of executing discriminationat a timing determined by the image forming apparatus 1 to be necessaryon the basis of the situation.

As an example, tire sheet feed tray information of the sheet feed tray11 named “tray 1” includes tire setting that tire “plain sheet” of “A4”size is “horizontally” held in the sheet feed tray 11 named “tray 1”.The type of sheet in the sheet feed tray 11 is set to be discriminatedat the timing when the image forming apparatus 1 determines thenecessity of discrimination on the basis of the situation.

In a case where a prim instruction is received from the user throughoperation panel 22 or the like, the image forming apparatus 1 refers tothe sheet feed tray information table to specify information of size,direction, and the type of the sheet held in sheet feed tray 11 or themanual feed tray 12 specified by the prim instruction. The image formingapparatus 1 determines various parameters related to the prim processingsuch as the conveyance speed and the fixing temperature in accordancewith the specified sheet information, and performs priming by the primerengine 108.

The sheet feed tray information may be reset in a case where the varioussensors 112 have detected that the sheet feed tray 11 has been opened orclosed, or where the change in the presence or absence of the sheetsheld in the sheet feed tray 11 or the manual feed tray 12 is detected bythe various sensors 112, or the like.

(Method for Setting Sheet Feed Tray Information Through Setting Screen)

FIGS. 5 and 6 are views schematically illustrating a setting screen ofsheet feed tray information displayed on the operation panel 22 in thefirst embodiment of the present invention.

Referring to FIG. 5, in a case where predetermined operation has beenreceived through operation panel 22, the image forming apparatus 1displays a first setting screen illustrated in FIG. 5 on the operationpanel 22. The first setting screen includes information set for thesheets held in each of the plurality of sheet feed trays 11 and themanual feed tray 12, a key KY1 for changing the setting, a key KY2 forcanceling the display of the setting screen, and a key KY3 forconfirming selection.

Referring to FIG. 6, in a case where any of the plurality of sheet feedtray s 11 and the manual feed tray 12 (here, the “tray 1”) is selectedon the first setting screen and the key KY3 is pressed, the imageforming apparatus 1 display s the second setting screen illustrated inFIG. 6 on the operation panel 22. The second setting screen is a screenthat receives operation for setting the sheet feed tray informationregarding the selected sheet feed tray 11 or the manual feed tray 12.The second setting screen includes a key KY4 which is a combo box thatreceives selection of a sheet size, a key KY5 which is a combo box thatreceives selection of a sheet direction, a key KY6 which is a combo boxthat receives selection of a sheet type, a key KY7 which is a combo boxthat receives the selection of the discrimination operation setting, akey KY8 for canceling the selected setting and returning to the firstsetting screen, and a key KY9 for confirming the selected setting.

In a case where the key KY9 is pressed on the second setting screen, theimage forming apparatus 1 updates the sheet feed tray information in thesheet feed tray information table so that the setting received throughthe second setting screen is to be reflected.

(Method for Setting Sheet Type in Sheet Feed Tray Information Based onMeasurement Results Obtained by Basis Weight Sensor)

The following description includes a case of setting the sheet type inthe sheet feed tray information of any sheet feed tray 11 among theplurality of sheet feed trays 11 and the manual feed tray 12.

The setting of the sheet type in the sheet feed tray information basedon the measurement result obtained by the basis weight sensor 23 may beperformed at any timing. At the time of setting the sheet type in thesheet feed tray information based on the measurement result obtained bythe basis weight sensor 23, the image forming apparatus 1 measures thebasis weight of the sheet to be conveyed by the basis weight sensor 23,and uses the sheet type discrimination table (example of the typediscrimination table) preliminarily stored in the storage 106 todiscriminate the type of sheet from the measured basis weight. The imageforming apparatus 1 sets the sheet type in the sheet feed trayinformation of the sheet feed tray 11 to the discriminated type.

FIG. 7 is a view schematically illustrating a conventional sheet typediscrimination table.

Referring to FIG. 7, the sheet type discrimination table is a tabledescribing a relationship between the basis weight and the sheet type.In the conventional sheet type discrimination table, one sheet type isassociated with one basis weight range so that the sheet type can beuniquely discriminated on the basis of the basis weigh.

Specifically, in a case where the measured basis weigh is in the rangeof “52 g/m² to 59 g/m²”, the sheet type is uniquely discriminated to bea “thin sheet”. In a case where the measured basis weigh is in the rangeof “60 g/m² to 90 g/m²”, the sheet type is uniquely discriminated to bea “plain sheet”. In a case where the measured basis weight is in therange of 91 g/m² to 120 g/m², the sheet type is uniquely discriminatedto be a “thick sheet 1”. In a case where the measured basis weight is inthe range of “121 g/m² to 157 g/m²”, the sheet type is uniquelydiscriminated to be a “thick sheet 1+”.

In the conventional sheet type discrimination table illustrated in FIG.7, the sheet types that achieves a conveyance speed that would cause noproblem in the image quality regardless of the required image qualitywhen the sheets within the basis weight range are conveyed areassociated with the basis weight.

As an example, in a case where the conventional sheet typediscrimination table is used, and when the measured basis weight is “92g/m²”, the sheet type is discriminated to be the thick sheet regardlessof the fact that the basis weight is close to the range of the basisweight of plain sheet (“60 g/m² to 90 g/m²”). However, for a user whogives priority to printing speed over printing quality, it is morepreferable that the sheet is discriminated to be the “plain sheet” witha high conveyance speed than discriminated to be the “thick sheet” witha low conveyance speed.

FIG. 8 is a view schematically illustrating an example of a sheet typediscrimination table stored in the storage 106 in the first embodimentof the present invention.

Referring to FIG. 8, the sheet type discrimination table of the presentembodiment prescribes a unique range that is a basis weight range inwhich the type of sheet is uniquely discriminated, and a selection rangethat is a basis weight range in which discriminated as one of a firsttype having relatively a large basis w eight and a second type having arelatively small basis weight. Two types of sheet are associated withthe selection range.

Specifically, the unique range includes a range of “52 g/m² to 54 g/m²”,a range of “65 g/m² to 84 g/m²”, a range of “95 g/m² to 114 g/m²”, and arange of “125 g/m² to 157 g/m²”. In a case where the measured basisweight is in the range of “52 g/m² to 54 g/m²”, the sheet type isuniquely discriminated to be the “thin sheet”. In a case where themeasured basis weight is in the range of “65 g/m² to 84 g/m²”, the sheettype is uniquely discriminated to be the “plain sheet”. In a case wherethe measured basis weight is in the range of “95 g/m² to 114 g/m²”, thesheet type is uniquely discriminated to be the “thick sheet 1”. In acase where the measured basis weight is in the range of “125 g/m² to 157g/m²”, the sheet type is uniquely discriminated to be the “thick sheet1+”.

The selection range includes a range of “55 g/m² to 64 g/m²”, a range of“85 g/m² to 94 g/m²”, and a range of “115 g/m² to 124 g/m²”. The rangeof “55 g/m² to 64 g/m²” is a range between the range of “52 g/m² to 54g/m²” which is uniquely discriminated to be the thin sheet, and therange of “65 g/m² to 84 g/m²” which is uniquely discriminated to be theplain sheet. Accordingly, in a case where the measured basis weight isin the range of “55 g/m² to 64 g/m²”, the sheet type is discriminated tobe “thin sheet or plain sheet”. The range of “85 g/m² to 94 g/m²” is arange between the range of “65 g/m² to 84 g/m²” which is uniquelydiscriminated to be the plain sheet, and the range of “95 g/m² to 114g/m²” which is uniquely discriminated to be the thick sheet 1.Accordingly, in a case where the measured basis weight is in the rangeof “85 g/m² to 94 g/m²”, the sheet type is discriminated to be “plainsheet or thick sheet 1”. The range of “115 g/m² to 124 g/m²” is a rangebetween the range of “95 g/m² to 114 g/m²” which is uniquelydiscriminated to be the thick sheet 1, and the range of “125 g/m² to 157g/m²” which is uniquely discriminated to be the thick sheet 1+.Accordingly, in a case where the measured basis weight is in the rangeof “115 g/m² to 124 g/m²”, the sheet type is discriminated to be “thicksheet 1 or thick sheet 1+”.

In a case where the basis weight measured by the basis weight sensor 23is a value within the unique range, the image forming apparatus 1 usesthe sheet type setting part 109 to set the sheet in the sheet feed trayinformation of the target sheet feed tray 11 to the sheet typeassociated with that unique range.

In a case where the basis weight measured by the basis weight sensor 23is a value within the selection range, the image forming apparatus 1uses the operation panel 22 to display a selection screen and receivesthe selection of the sheet type through the selection screen. Theselection screen is a screen that receives operation of selecting thesheet type from among the types corresponding to two individual uniqueranges each having a basis weight range adjacent to the selection range.In the case of displaying the selection screen, the image formingapparatus 1 uses the sheet type setting part 109 to set the sheet typein the sheet feed tray information of the target sheet feed tray 11 tothe type received through the selection screen.

FIG. 9 is a view schematically illustrating a selection screen displayedon the operation panel 22 in a case where the basis weight measured bythe basis weight sensor 23 is a value within the selection range of “85g/m² to 94 g/m²” in the first embodiment of the present invention.

Referring to FIG. 9, in a case, as an example, where the basis weightmeasured by basis weight sensor 23 is in the selection range “85 g/m² to94 g/m²” (selection range in which the sheet type is discriminated to be“plain sheet or thick sheet 1”), a pop-up PP1 is displayed on theoperation screen displayed during printing. The pop-up PP1 includes akey KY10 that receives the selection of “plain sheet” and a key KY11that receives the selection of “thick sheet 1”.

FIG. 10 is a view schematically illustrating another example of a sheettype discrimination table stored in the storage 106 in the firstembodiment of the present invention. Note that, for the convenience ofdescription. FIG. also illustrates the conveyance speeds correspondingto the sheet types.

Referring to FIG. 10, in a case where the conveyance speed set by thesheet type corresponding to each of the two unique ranges having therange of basis weight adjacent to the selection range is the same, theconveyance speed cannot be increased regardless of which sheet type isset. For this reason, a selection range may be provided between the twounique ranges in a specific case where the conveyance speeds set for thesheet types corresponding to each of the two unique ranges are differentfrom each other.

Specifically, the sheet type discrimination table includes a selectionrange that receives selection of sheet type from among the “thin sheetand plain sheet” set between the range of “52 g/m² to 54 g/m²” uniquelydiscriminated to be a thin sheet and for which the conveyance speed of“30 sheets/minute” is set and the range of “65 g/m² to 84 g/m²” uniquelydiscriminated to be a plain sheet and for which the conveyance speed of“36 sheets/minute” is set. In addition, a selection range that receivesselection of sheet type from among the “plain sheet and thick sheet 1”is set between the range of “65 g/m² to 84 g/m²” uniquely discriminatedto be the plain sheet and for which the conveyance speed of “36sheets/minute” is set and the range of “95 g/m² to 120 g/m²” uniquelydiscriminated to be the thick sheet 1 and for which the conveyance speedof “30 sheets/minute” is set. Meanwhile, the conveyance speed set forthe thick sheet 1 and the conveyance speed set for the thick sheet 1+are both “30 sheets/minute”. Therefore, there is no selection rangeprovided between the range of “95 g/m² to 120 g/m²” uniquelydiscriminated to be the thick sheet 1 and for which the conveyance speedof “30 sheets/minute” is set and the range of “121 g/m² to 157 g/m²”uniquely discriminated to be the thick sheet 1+ and for which theconveyance speed of “30 sheets/minute” is set.

(Operation in the Case of Receiving Sheet Type Setting Through SecondSetting Screen after Setting to Sheet Type Selected Through SelectionScreen)

FIG. 11 is a view schematically illustrating a second setting screen ina case where the setting of the sheet type is received through thesecond setting screen after setting is performed to the sheet typeselected through the selection screen in the first embodiment of thepresent invention.

Referring to FIG. 11, in a case where the second setting screen (exampleof the setting screen) is to be displayed on the operation panel 22after the sheet type in the sheet feed tray information of the targetsheet feed tray 11 is set to the sleet type selected on the selectionscreen, the image forming apparatus 1 may display the second settingscreen that receives operation to set the sheet type from among thetypes corresponding to each of the two unique ranges being options onthe selection screen.

Here is an assumed case where the options for the “plain sheet” or the“thick sheet 1” are displayed on the selection screen, and the sheettype in the sheet feed tray information of the target sheet feed tray 11is set to the sheet type selected on the selection screen. The secondsetting screen displayed after setting in this case includes optionslimited to the plain sheet or the thick sheet 1. That is, the secondsetting screen includes a key KY12 that receives the selection of “plainsheet” and a key KY13 that receives the selection of “thick sheet 1”instead of the key KY6 (FIG. 6) which is the combo box that receives theselection of the sheet type.

In this case, the image forming apparatus 1 uses the sheet type settingpart 109 to change the sheet type setting in the sheet feed trayinformation of the target sheet feed tray 11 to the type received on thesecond setting screen illustrated in FIG. 11.

In a case where the basis weight measured by the basis weight sensor 23is a value within the unique range, there is no need for the imageforming apparatus 1 to receive operation to set the sheet type throughthe setting screen after completion of setting the sheet type in sheetfeed tray information for the target sheet feed tray 11.

(Flowchart)

FIG. 12 is a flowchart illustrating operation of the image formingapparatus 1 according to the first embodiment of the present invention.

Referring to FIG. 12, the CPU 102 measures the basis weight of the sheetpassing the measurement position of the basis weight sensor 23 at anarbitrary timing using the basis weight sensor 23 (S1). Next, the CPU102 uses the sheet type discrimination table to discriminate whether thebasis weight measured by the basis weight sensor 23 is a value within aunique range (S3).

In a case where it is discriminated in step S3 that the basis w eightmeasured by the basis weight sensor 23 is a value within a unique range(YES in S3), the CPU 102 sets the sheet type in the sheet feed trayinformation of the sheet feed tray 11 that has fed the sheet to thesheet type discriminated from the measured basis weight (S5), andproceeds to processing of step S7.

In a case where it is discriminated in step S3 that the basis weightmeasured by the basis weight sensor 23 is not a value within the uniquerange (NO in S3), the CPU 102 displays a selection screen (S11). The CPU102 sets the sheet type in the sheet feed tray information of the sheetfeed tray 11 that has supplied the sheet to the type selected throughthe selection screen (S13), and proceeds to processing of step S7.

In step S7, the CPU 102 sets various parameters such as the conveyancespeed in accordance with the set sheet type (S7), performs printing(S9), and finishes the processing.

According to the present embodiment, the selection of the sheet type isreceived from the selection screen in a case where the selection rangeis provided as the basis weight range on the sheet type discriminationtable, and where the basis weight measured by the basis weight sensor 23is a value within the selection range. This configuration enables a userwho does not require high-quality printing to select the sheet typehaving a high conveyance speed, leading to suppression of an increase inthe time required for printing.

Second Embodiment

In a case where the basis weight measured by the basis weight sensor 23is a value within the selection range, it might be annoying for the userto always select the sheet type from the selection screen. To handlethis, the present embodiment will describe an exemplary case where thenecessity discrimination part 114 is used to perform selection necessitydetermination processing to discriminate whether there is a need todisplay the selection screen, and the selection screen is not to bedisplayed when it is discriminated that there is no need to display theselection screen in a case where the basis weight measured by the basisweight sensor 23 is a value within the selection range.

(Flowchart)

FIG. 13 is a flowchart illustrating operation of the image formingapparatus 1 according to the second embodiment of the present invention.

Referring to FIG. 13, in a case where it is discriminated, in step S3 ofthe flowchart of FIG. 12, that the sheet type cannot be uniquelydiscriminated from the measured basis weight (NO in S3), the CPU 102performs the selection necessity determination processing describedbelow (S21) and discriminates whether there is a need to display theselection screen (S23).

In a case where it is discriminated in step S23 tint there is a need todisplay the selection screen (YES in S23), the CPU 102 performs theprocessing of step S11 and subsequent steps in the flowchart of FIG. 12.

In step S23, when it is discriminated that there is no need to displaythe selection screen (NO in S23), the CPU 102 does not display theselection screen, and sets the sheet type in the sheet feed trayinformation of the sheet feed tray 11 that has supplied the sheet to thesheet type determined under the other conditions (S25), and performs theprocessing of step S7 and subsequent steps in the flowchart of FIG. 12.

(First Example of Selection Necessity Determination Processing)

In a case, as a first example of the selection necessity determinationprocessing, where the change of the type of the sheet held in the sheetfeed tray 11 has not been detected by various sensors 112 in a statewhere the sheet type in the sheet feed tray information of the sheetfeed tray 11 is set, it is allowable to determine that there is no needto display the selection screen.

In addition, in a case where it is determined that there is no need todisplay the selection screen, the setting of the sheet type of the sheetfeed tray information of the sheet feed tray 11 does not have to bechanged.

The case where the change of the sheet held in the sheet feed tray 11has been detected is a case where the opening and closing of the sheetfeed tray 11 has been detected by the various sensors 112, andthereafter a change in attributes of the sheet other than the type(sheet size, sheet color, or the load amount of sheets on the sheet feedtray 11, or the like) has been detected by the various sensors 112.

The case where the change of the sheet held in the sheet feed tray 11has been detected may be a case where the change of the load amount ofsheets held in the sheet feed tray 11 has been detected by the varioussensors 112.

The case where the change of the sheet held in the sheet feed tray 11has been detected may be a case where the change of the size of thesheet stored in the sheet feed tray 11 has been detected by the varioussensors 112.

The case where the change of the sheet held in the sheet feed tray 11has been detected may be a case where the change of the color of thesheet conveyed from the sheet feed tray 11 has been detected by thevarious sensors 112.

FIG. 14 is a subroutine of selection necessity determination processing(S21) in the first example of the second embodiment of the presentinvention.

Referring to FIG. 14, the CPU 102 discriminates (S31) in the selectionnecessity determination processing (S21) whether the sheet of sheet feedtray 11 has been changed on the basis of the detection results obtainedby the various sensors 112.

In a case where it is discriminated in step S31 that the sheet of thesheet feed tray 11 has been changed (YES in S31), the CPU 102 determinesthat there is a need to display the selection screen (S33), and thencontrol is returned.

In a case where it is discriminated in step S31 that the sheet of thesheet feed tray 11 has not been changed (NO in S31), the CPU 102determines that there is no need to display the selection screen (S35),and then control is returned.

(Second Example of Selection Necessity Determination Processing)

As a second example of the selection necessity determination processing,it is allowable to determine that there is no need to display theselection screen in a case where the type of job received by the imageforming apparatus 1 is a specific type (in a case, in particular, wherethe job is a print job for management of the image forming apparatus 1).In a case where it is determined tint there is no need to display theselection screen, the types of sheets held in the target sheet feed tray11 may be set by the method described in the following items (1) to (4).

(1) In a case where the image forming apparatus 1 executes a print job(example of a specific type of job) for management of the image formingapparatus 1, the quality necessary for an image (image containinginformation for management of the image forming apparatus 1, such assetting values and status of the image forming apparatus 1) formed on asheet is a low level image that is satisfactory as long as it can beread.

Therefore, in a case where the type of job received by the image formingapparatus 1 is a print job for management of the image forming apparatus1, or the like, it is allowable to determine that there is no need todisplay the selection screen and suppress displaying the selectionscreen. This configuration would make it possible to reduce the worktime of the service person or administrator of the image formingapparatus 1, leading to reduction of the service cost and themanagement. The type of job may also be determined on the basis ofinformation such as whether the state of the image forming apparatus 1is in the setup state or whether the image to be printed includes areport on maintenance of the image forming apparatus 1.

In a case where it is determined that there is no need to display theselection screen, the type of two sheets associated with the selectionrange including the basis weight measured by the basis weight sensor 23is specified, and the conveyance speed of each of the two types ofsheets may be discriminated on the basis of the conveyance speeddiscrimination table illustrated in FIG. 15 (example of the conveyancespeed discrimination table), and it is allowable to set the sheet typein the sheet feed tray information of the target sheet feed tray 11 tothe type having the higher conveyance speed out of the two types.

FIG. 15 is a view schematically illustrating a conveyance speeddiscrimination table stored in the storage 106 in the second embodimentof the present invention.

Referring to FIG. 15, the conveyance speed discrimination table is atable describing the relationship between the sheet type and theconveyance speed. According to the conveyance speed discriminationtable, it can be observed that the conveyance speed of thin sheet is “30sheets/minute”, the conveyance speed of plain sheet is “36sheets/minute”, the conveyance speed of thick sheet 1 is “30sheets/minute” and the conveyance speed of thick sleet 1+ is “30sheets/minute”.

In a case, as an example, where “thin sheet and plain street” isassociated with the selection range including the basis weight measuredby the basis weight sensor 23, the conveyance speed of the thin sheet(30 sheets/minute) and tire conveyance speed of the plain sheet (36sheets/minute) are discriminated on the basis of the conveyance speeddiscrimination table, and then, tire sheet type in tire sheet feed trayinformation of the target sheet feed tray 11 is set to the plain sheet,which is tire type with the higher conveyance speed.

(2) In a case where the job mode is monochrome mode, high quality is notrequired for the image formed on the sheet and therefore, it is possibleto increase the street conveyance speed. In contrast in a case wheretire mode of the job is color mode, high quality is required for theimage formed on the sheet.

Accordingly, when the job mode is a first mode (here, monochrome mode),it is allowable to determine that there is no need to display tireselection screen and there it is allowable to use the conveyance speeddiscrimination table illustrated in FIG. 15 to set the type of sheetheld in the target street feed tray 11 on tire basis of tire basisweight measured by tire basis weight sensor 23. Moreover, when tire jobmode is a second mode (here, color mode), it is allowable to determinethat there is no need to display the selection screen and then, it isallowable to use the image quality-priority sheet type discriminationtable (example of another type discrimination table) illustrated in FIG.16 to set the type of sheet in the sheet feed tray information of thetarget sheet feed tray 11 on the basis of the basis weight measured bythe basis weigh sensor 23.

FIG. 16 is a view schematically illustrating an image quality-prioritysheet type discrimination table stored in a storage 106 in the secondembodiment of the present invention.

Referring to FIG. 16, the image quality-priority sheet typediscrimination table, one sheet type is associated with one basis weightrange so that the sheet type can be uniquely discriminated on the basisof the basis weight.

Specifically, in a case where the measured basis weight is in the rangeof “52 g/m² to 59 g/m²”, tire sheet type is uniquely discriminated to bea “thin sheet”. In a case where the measured basis weight is in therange of “60 g/m² to 90 g/m²”, the sheet type is uniquely discriminatedto be a “plain sheet”. In a case where the measured basis weight is inthe range of 91 g/m² to 120 g/m², the sheet type is uniquelydiscriminated to be a “thick sheet 1”.

In a case where the measured basis weight is in the range of “121 g/m²to 157 g/m²”, the sheet type is uniquely discriminated to be a “thicksheet 1+”.

In the image quality-priority sheet type discrimination table, the sheettypes that achieves the conveyance speed that would cause no problem inthe image quality regardless of the required image quality when thesheets within the basis weight range are conveyed are associated withthe basis weight.

(3) In a case where the job mode is low resolution print mode, highquality is not required for the image formed on the sheet, andtherefore, it is possible to increase the sheet conveyance speed. Incontrast, in a case where the mode of the job is a high resolution printmode, high quality is required for an image formed on a sheet.

Accordingly, when the job mode is a first mode (here, low resolutionprint mode), it is allowable to determine that there is no need todisplay the selection screen and then, it is allowable to use theconveyance speed discrimination table illustrated in FIG. 15 to set thetype of sheet held in the target sheet feed tray 11 on the basis of thebasis weight measured by the basis weight sensor 23. Furthermore, in acase where it is determined that there is no need to display theselection screen and when the mode of the job is the second mode (here,a prim mode with high resolution), it is allowable to determine thatthere is no need to display the selection screen, and then, it isallowable to use the image quality-priority sheet type discriminationtable illustrated in FIG. 16 to set the type of sheet held in the targetsheet feed tray 11 on the basis of the basis weight measured by thebasis weight sensor 23.

(4) In a case where the job mode is a print inode with document imagequality of text or duplicated photograph, high quality is not requiredfor the image formed on the sheet, and therefore, it is possible toincrease the sheet conveyance speed. In contrast, in a case where themode of the job is a print mode with the document image quality of aphoto or a map, high quality is required for the image formed on thesheet.

Therefore, when the job mode is the first mode (here, the prim mode withthe document image quality of the text or duplicated photograph), it isallowable to determine that there is no need to display the selectionscreen and the sheet type held in the target sheet feed tray 11 may beset using the conveyance speed discrimination table illustrated in FIG.15 on the basis of the basis weigh measured by the basis weigh sensor23. Moreover, when the job mode is a second mode (here, a print modewith document image quality of photograph or map), it is allowable todetermine that there is no need to display the selection screen andthen, it is allowable to use the image quality-priority sheet typedissemination table illustrated in FIG. 16 to set the type of sheet heldin the target sheet feed tray 11 on the basis of the basis weightmeasured by the basis weigh sensor 23.

FIG. 17 is a subroutine of selection necessity determination processing(S21) in a second example of the second embodiment of the presentinvention.

Referring to FIG. 17, the CPU 102 discriminates in the selectionnecessity determination processing (S21) whether the job received byimage forming apparatus 1 is a job of a predetermined type (S41).

In step S41, in a case where it is discriminated that the job receivedby the image forming apparatus 1 is a job of a predetermined type (YESin S41), the CPU 102 determines that there is no need to display theselection screen (S43), and uses either the conveyance speeddiscrimination table or the image quality-priority sheet typediscrimination table to set the sheet type in the sheet feed trayinformation of the sheet feed tray 11 (S45), and then control isreturned.

In step S41, when it is discriminated that the job received by the imageforming apparatus 1 is not a job of a predetermined type (NO in S41),the CPU 102 determines that there is a need to display the selectionscreen (S47), and then control is returned.

(Third Example of Selection Necessity Determination Processing)

In a case where the user is away from the image forming apparatus 1, theuser cannot operate the selection screen, and this causes stoppage ofprinting while the selection screen is being displayed. In order toavoid such a situation, it is allowable, as a third example of theselection necessity determination processing, to determine that there isno need to display the selection screen in a case where the position ofthe user is away from the position of the image forming apparatus 1 by adistance more than a predetermined distance. The position of the usermay be specified on the basis of the user's position information andentry/exit information acquired by the position information acquisitionpan 113.

FIG. 18 is a subroutine of selection necessity determination processing(S21) in the third example of the second embodiment of the presentinvention.

Referring to FIG. 18, the CPU 102 acquires, in the selection necessitydetermination processing (S21), user's position information orentry/exit information by the position information acquisition part 113(S51), and discriminates whether the user is in the vicinity of theimage forming apparatus 1 (S53).

In a case where it is discriminated in step S53 that the user is in thevicinity of the image forming apparatus 1 (YES in S53), the CPU 102discriminates that there is a need to display the selection screen(S55), and then control is returned.

In a case where it is discriminated in step S53 that the user is not inthe vicinity of the image forming apparatus 1 (NO in S53), the CPU 102discriminates that there is no need to display the selection screen(S57), and then control is returned.

(Fourth Example of Selection Necessity Determination Processing)

When performing post-processing such as stapling, the necessity ofsetting of post-processing such as the number of sheets that can bestapled, whether or not to punch, and the number of folds is determinedby the basis weight of the sheet. In a case where post-processing isperformed by treating a sheet type having a large actual basis weight asa sheet type having a small basis weight the thickness of the sheetsmight be larger than the thickness that can be processed by thepost-processing device, leading to a concern of a failure in thepost-processing device.

Therefore, in a case, as a fourth example of tire selection necessitydetermination processing, where predetermined post-processing is set forthe job, it is allowable to determine that there is no need to displaythe selection screen and set the sheet of the street held in the sheetfeed tray to the type having tire larger basis weight (first type) outof the two types of sheets associated with the selection rangesincluding the basis weight measured by tire basis weight sensor 23.

FIG. 19 is a subroutine of selection necessity determination processing(S21) in the fourth example of the second embodiment of the presentinvention.

Referring to FIG. 19, the CPU 102 discriminates in the selectionnecessity determination processing (S21) whether the setting ofpost-processing has been added to the job (S61).

In a case where it is discriminated in step S61 that the post-processingsetting has been added to the job (YES in S61), the CPU 102discriminates that there is no need to display the selection screen(S63). Next, the CPU 102 sets tire sheet type in the sheet feed trayinformation of tire sheet feed tray 11 to tire type having a largerbasis weight out of the two sheet types associated with tire selectionranges including the basis weight measured by tire basis weight sensor23 (S65), and then control is returned.

In a case where it is discriminates in step S61 that the post-processingsetting is not added to the job (NO in S61), the CPU 102 discriminatesthat there is a need to display the selection screen (S67), and thencontrol is returned.

Note that the configuration of the image forming apparatus in thepresent embodiment and the operation other than those described aboveare similar to those in the first embodiment, and therefore thedescription thereof will not be repeated.

Third Embodiment

In a case where the sheet type in the sheet feed tray information of thesheet feed tray 11 is set by the method described in the first andsecond embodiments, there is an occasion where the sheet type is foundout to be inappropriate alter setting. Therefore, the present embodimentwill describe an example of performing setting change processing in apredetermined case and changing the sheet type in the sheet feed trayinformation of the sheet feed tray 11.

(First Example of Setting Change Processing)

As a first example of the setting change processing, when it isdetermined that there is no need to display the selection screen and thequality of the evaluated image is lower than a predetermined value, theselection screen for change may be displayed, and the sheet type settingpan 109 may be used to change the sheet type in the sheet feed trayinformation of the sheet feed tray 11 to the type for which theselection has been received through the selection screen for the change.The selection screen for the change may be any screen that receivesoperation to select the sheet type from the first and second types, andmay be the same screen as the selection screen illustrated in FIG. 9.

FIG. 20 is a flowchart illustrating setting change processing performedby the image forming apparatus 1 in the first example of the thirdembodiment of the present invention.

Referring to FIG. 20, after setting the sheet type in the sheet feedtray information of sheet feed tray 11, the CPU 102 discriminateswhether it is determined that there is no need to display the selectionscreen (S71) in the selection necessity determination processing (S21)at the time of setting the sheet type in the sheet feed tray informationof the sheet feed tray 11.

In a case where it is discriminated in step S71 that the determinationis that there is no need to display the selection screen (YES in S71),the CPU 102 detects the density of the toner image formed on theintermediate transfer belt 20 a by the various sensors 112 (IDC sensor)and evaluates the quality of an image on the basis of a detection result(S73). Subsequently, the CPU 102 disseminates whether the quality of theimage is a predetermined value or less (S75).

In a case where it is discriminated in step S71 that the determinationis that there is a need to display the selection screen (NO in S71), orit is discriminated in step S75 that the quality of the image is notless than the predetermined value (NO in S75), the CPU 102 finishes theprocessing.

In a case where it is discriminated in step S75 that the quality of theimage is a predetermined value or less (YES in S75), the CPU 102displays the selection screen for the change having two sheet typesassociated with the selection range including the basis weight measuredby the basis weight sensor 23 as an option (S77). The CPU 102 changesthe sheet type in the sheet feed tray information of the sheet feed tray11 to the selected sheet type (S79), and finishes the processing.

(Second Example of Setting Change Processing)

As a second example of the setting change processing, when it isdetermined that there is no need to display the selection screen and thenumber of occurrences of jams exceeds a predetermined number, theselection screen for change may be displayed, and the sheet type settingpart 109 may be used to change the sheet type in the sheet feed trayinformation of the sheet feed tray 11 to the type for which theselection has been received through the selection screen for the change.

Here, the number of occurrences of jams to be counted may be simply jamsrelated to sheet conveyance or printing, or simply jams related to thesheet conveyed from the sheet feed tray 11 in which the sheet type hasbeen set without displaying the selection screen.

FIG. 21 is a flowchart illustrating setting change processing performedby the image forming apparatus 1 in the second example of the thirdembodiment of the present invention.

Referring to FIG. 21, after setting the sheet type in the sheet feedtray information of sheet feed tray 11, the CPU 102 discriminateswhether it is determined that there is no need to display the selectionscreen (S81) in the selection necessity determination processing (S21)at the time of setting the sheet type in the sheet feed tray informationof the sheet feed tray 11.

In step S81, in a case where it is discriminated that determination isthat there is no need to display the selection screen (YES in S81), theCPU 102 reads the number of occurrences of jams from the storage 106(S83), and discriminates whether the read number of occurrences of jamsexceeds a predetermined value (S85).

In a case where it is discriminated in step S81 that the determinationis that there is a need to display the selection screen (NO in S81), orit is discriminated in step S85 that the read number of occurrences ofjams does not exceed a predetermined value (NO in S85), the CPU 102finishes the processing.

In a case where it is discriminated in step S85 that the read number ofoccurrences of jams has exceeded the predetermined value (YES in S85),the CPU 102 displays the selection screen for the change having twosheet types associated with the selection range including the basisweight measured by the basis weight sensor 23 as an option (S87). TheCPU 102 changes the sheet type in the sheet feed tray information of thesheet feed tray 11 to the selected sheet type (S89), and finishes theprocessing.

(Third Example of Setting Change Processing)

As a third example of the setting change processing, in a case, aftersetting the sheet type, where the quality of the image evaluated by theevaluation pan 115 is lower than a predetermined value, and the basisweight measured by the basis weight sensor 23 is within a selectionrange, and where the type of sheet that has been set and the type ofsheet discriminated by using the image quality-priority typediscrimination table are different from each other, the sheet typesetting part 109 may be used to change the sheet type in the sheet feedtray information of the sheet feed tray 11 to the sheet typediscriminated by using the image quality-priority type discriminationtable.

FIG. 22 is a flowchart illustrating setting change processing performedby the image forming apparatus 1 in the third example of the thirdembodiment of the present invention.

Referring to FIG. 22, after setting the sheet type of the sheet feedtray information of sheet feed tray 11, the CPU 102 detects the densityof the toner image formed on the intermediate transfer belt 20 a usingvarious sensors 112 (IDC sensors) and evaluates the quality of the imageon the basis of the detection result (S91). Subsequently, the CPU 102discriminates whether the quality of the image is a predetermined valueor less (S93).

In a case where it is discriminated in step S93 that the quality of theimage is the predetermined value or less (YES in S93), the CPU 102discriminates whether the basis weight measured by the basis weightsensor 23 is a value within a selection range (S95).

In a case where it is discriminated in step S95 that the basis weightmeasured by the basis weight sensor 23 is a value within the selectionrange (YES in S95), the CPU 102 discriminates whether the sheet type setas the sheet feed tray information of the sheet feed tray 11 differsfrom the sheet type discriminated by image quality-priority table (S97).

The CPU 102 finishes the processing in a case where it is discriminatedin step S93 that the quality of the image is not less than thepredetermined value (NO in S93), or where it is discriminated in stepS95 that the basis weight measured by basis weight sensor 23 is notwithin the selection range (NO in S95), or where it is discriminated instep S97 that the sheet type set as the sheet feed tray information ofthe sheet feed tray 11 does not differ from the sheet type discriminatedin the image quality-priority table (NO in S97).

In a case where it is discriminated in step S97 that the sheet type setas the sheet feed tray information of the sheet feed tray 11 isdifferent from the sheet type discriminated in the imagequality-priority table (YES in S97), the CPU 102 changes the sheet typein the sheet feed tray information of the sheet feed tray 11 from thebasis weight measured by the basis weight sensor 23 to the typediscriminated using the image quality-priority sheet type discriminationtable (S99), and then finishes the processing.

(Fourth Example of Setting Change Processing)

As a fourth example of the setting change processing, in a ease wherethe basis weight measured by the basis weight sensor 23 is a valuewithin the selection range and the number of occurrences of jams afterthe sheet type setting exceeds a predetermined number, it is allowable,by using the sheet type setting part 109, to change the sheet type inthe sheet feed tray information of the sheet feed tray 11 to the type ofthe lower conveyance speed described in the conveyance speeddiscrimination table out of two types of sheets associated with theselection ranges including the basis weight measured by the basis weightsensor 23. This is because a slower conveyance speed reduces thepossibility of jam.

Here, the number of occurrences of jams to be counted may be simply jamsrelated to sheet conveyance or printing, or simply jams attributed tothe sheet conveyed from the target sheet feed tray 11.

FIG. 23 is a flowchart illustrating setting change processing performedby the image forming apparatus 1 in the fourth example of the thirdembodiment of the present invention.

Referring to FIG. 23, after setting the sheet type in the sheet feedtray information of the sheet feed tray 11, the CPU 102 discriminateswhether the basis weight measured by the basis weigh sensor 23 is avalue within a selection range (S101).

In a case where it is discriminated in step S101 that the basis weighmeasured by the basis weigh sensor 23 is a value within a selectionrange (YES in S101), the CPU 102 reads the number of occurrences of jamsfrom the storage 106 (S103), and discriminates whether the read numberof occurrences of jams exceeds a predetermined value (S105).

In a case where it is discriminated in step S101 that the basis weighmeasured by the basis weigh sensor 23 is not a value within a selectionrange (NO in S101), or it is discriminated in step S105 that the readnumber of occurrences of jams does not exceed a predetermined value (NOin S105), the CPU 102 finishes the processing.

In step S105, when it is discriminated that the read number ofoccurrences of jams exceeds the predetermined value (YES in S105), theCPU 102 changes the sheet type in the sheet feed tray information of thesheet feed tray 11 to the type of the lower conveyance speed describedin the conveyance speed discrimination table out of two types of sheetsassociated with the selection ranges (S107), and finishes theprocessing.

Note that the configuration of the image forming apparatus in thepresent embodiment and the operation other than those described aboveare similar to those in the first embodiment, and therefore thedescription thereof will not be repealed.

OTHERS

The embodiments described above and the examples in the embodiments canbe combined with each other as appropriate.

The processing in the above-described embodiments may be performed bysoftware or may be performed using a hardware circuit. Furthermore, itis also possible to provide a program for executing the processing inthe above-described embodiments, and the program may be recorded on arecording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM,a RAM, a memory card and supplied to the user. The program is executedby a computer such as a CPU. Furthermore, the program may be downloadedto the apparatus via a communication line such as the Internet.

Although embodiments of the present invention have been described andillustrated in detail, the disclosed embodiments are made for purposesof illustration and example only and not limitation. The scope of thepresent invention should be interpreted by terms of the appended claims,and is intended to include all modifications within the meaning andscope, which are equivalent to the scope of claims.

What is claimed is:
 1. A sheet type discrimination device comprising: aholder that holds a sheet; a conveyor that conveys a sheet from theholder along a conveyance path; a measurer that measures a basis weightof the sheet conveyed along the conveyance path; a storage that stores atype discrimination table describing a relationship between the basisweight and a type of a sheet; and a hardware processor that sets thetype of the sheet field in the holder on the basis of the basis weightmeasured by the measurer, wherein the type discrimination tableprescribes a unique range being a range of basis weight in which thesheet type is uniquely discriminated, and a selection range being arange of basis weight in which the sheet type is discriminated intoeither of a first type in which the basis weight is relatively large anda second type in which the basis weight is relatively small, the sheettype discrimination device further comprising a selection screen displaythat displays a selection screen being a screen that receives operationof selecting the sheet type from the first and second types in a casewhere the basis weight measured by the measurer is within the selectionrange, and that receives selection through the selection screen, and ina case where the selection screen is displayed, the hardware processorsets the type of the sheet held in the holder to the type receivedthrough the selection screen.
 2. The sheet type discrimination deviceaccording to claim 1, wherein the unique range includes: a first uniquerange being a range of basis weight in which the sheet type is uniquelydiscriminated to be the first type; and a second unique range being arange of basis weight in which the sheet type is uniquely discriminatedto be the second type, having a conveyance speed of the first sheet typea conveyance speed of the second sheet type different from each other,and the selection range is set between the first unique range and thesecond unique range.
 3. The sheet type discrimination device accordingto claim 1, further comprising: a setting screen display that display sa setting screen that receives operation to set the type of sheet heldin the holder and receives setting of the sleet type through the settingscreen after setting of the sheet type held in the holder by thehardware processor, wherein the hardware processor changes the settingof the type of the sheet held in the holder to the type for whichsetting has been received by the setting screen display, and the settingscreen display displays the setting screen that receives operation ofsetting a sheet type out of the first type and the second type.
 4. Thesheet type discrimination device according to claim 3, wherein, in acase where the basis weight measured by the measurer is a value withinthe unique range, the setting screen display does not receive operationof setting the sheet type through the setting screen.
 5. The sheet typediscrimination device according to claim 1, wherein the hardwareprocessor discriminates whether there is a need to display the selectionscreen, and in a case where the basis weight measured by the measurer isa value within the selection range and when the hardware processordetermines that there is no need to display the selection screen, theselection screen display does not display the selection screen.
 6. Thesheet type discrimination device according to claim 5, furthercomprising a change detector that detects a change in the type of thesheet field in the holder, wherein, in a case where the change detectorhas not detected a change in the type of the sheet field in the holderin a state where the type of the sheet held in the holder is set, thehardware processor determines that there is no need to display theselection screen.
 7. The sheet type discrimination device according toclaim 6, wherein, in a case where the change detector has not detected achange in the type of sheet held in the holder in a state where the typeof the sheet held in the holder is set, the hardware processor does notchange the setting of the type of the sheet held in the holder.
 8. Thesheet type dissemination device according to claim 5, further comprisingan image former that forms an image in accordance with a received job,wherein, in a case where the type of the job is a specific type, thehardware processor determines that there is no need to display theselection screen.
 9. The sheet type discrimination device according toclaim 8, wherein the specific type includes a print job for managementof an image forming apparatus.
 10. The sheet type discrimination deviceaccording to claim 8, wherein the storage further stores a conveyancespeed discrimination table describing a relationship between the type ofthe sheet and a conveyance speed, and in a case where the hardwareprocessor has determined that there is no need to display the selectionscreen, the hardware processor specifies the conveyance speed of each ofthe first and second types of sheets on the basis of the conveyancespeed discrimination table, and sets the type of the sheet field in theholder to the type having the higher conveyance speed among the firstand second types.
 11. The sheet type discrimination device according toclaim 5, further comprising an image former that forms an image inaccordance with the received job, wherein the storage further stores: aconveyance speed discrimination table describing a relationship betweenthe type of sheet and the conveyance speed; and another typediscrimination table describing a relationship between the basis weightand the type of sheet and uniquely prescribing the type of the sheetwith respect to the basis weight, the hardware processor determines thatthere is no need to display the selection screen in a case where themode of the job is a specific mode, in a case where it is determined bythe hardware processor that there is no need to display the selectionscreen and where the mode of the job is the first mode, the hardwareprocessor sets the type of the sheet held in the holder using theconveyance speed discrimination table on the basis of the basis weightmeasured by the measurer, and in a ease where it is determined by thehardware processor that there is no need to display the selection screenand where the mode of the job is a second mode different from the firstmode, the hardware processor sets the type of sheet held in the holderusing the other type discrimination table on the basis of the basisweight measured by the measurer.
 12. The sheet type discriminationdevice according to claim 5, further comprising: an image former thatforms an image in accordance with a job received from a user, and aposition acquisitor that acquires information regarding the position ofthe user, wherein the hardware processor determines that there is noneed to display the selection screen in a case where the position of theuser is away from the position of the image forming apparatus more thana predetermined distance.
 13. The sheet type discrimination deviceaccording to claim 5, further comprising an image former that forms animage in accordance with a received job, wherein in a case wherepredetermined post-processing is set for the job, the hardware processordetermines that there is no need to display the selection screen, andthe hardware processor sets the type of the sheet held in the holder tothe first type.
 14. The sheet type discrimination device according toclaim 5, further comprising: another selection screen display thatperforms, in a predetermined case after the type of the sheet is set bythe hardware processor, displaying another selection screen being ascreen that receives operation of selecting the type of the sheet fromamong the first and second types and receiving selection through theother selection screen, wherein the hardware processor changes, in acase where the other selection screen is displayed, the sheet type setby the hardware processor to the type for which selection has beenreceived by the other selection screen display.
 15. The sheet typediscrimination device according to claim 14, wherein the hardwareprocessor evaluates quality of an image formed by the image former aftersetting of the type of the sheet by the hardware processor, and in acase where it is determined by the hardware processor that there is noneed to display the selection screen, and where the quality evaluated bythe hardware processor is lower than a predetermined value, the otherselection screen display displays the other display screen, and receivesselection through the other selection screen.
 16. The sheet typediscrimination device according to claim 14, wherein, in a case where itis determined, by the hardware processor, that there is no need todisplay the selection screen, and where the number of occurrences ofjams exceeds a predetermined number, the other selection screen displaydisplays the other display screen, and receives selection through theother selection screen.
 17. The sheet type discrimination deviceaccording to claim 1, wherein the hardware processor changes, in a casewhere an evaluation value of the quality of the image formed by theimage former after the type of the sheet is set by the hardwareprocessor is lower than a predetermined value, where the basis weightmeasured by the measurer is within the selection range, and where thetype of the sheet set by the hardware processor and the type of thesheet discriminated by another type discrimination table describing arelationship between the basis weight and the sheet type and uniquelyprescribing the type of sheet with respect to the basis weight aredifferent from each other, the type of sheet set by the hardwareprocessor to the type discriminated by using the other typedissemination table.
 18. The sheet type discrimination device accordingto claim 1, wherein the hardware processor changes, in a case where thebasis weight measured by the measurer is a value within the selectionrange, and the number of occurrences of jams after setting of the typeof the sheet by the hardware processor exceeds a predetermined number,the type of sheet set by the hardware processor to the type having aslower conveyance speed among the first and the second type.
 19. Anon-transitory recording medium storing a computer readable program forcontrolling a sheet type discrimination device including: a holder thatholds a sheet; a conveyor that conveys a sheet from the holder along aconveyance path; a measurer that measures a basis weight of the sheetconveyed along the conveyance path; and a storage that stores a typediscrimination table describing a relationship between the basis weightand a type of the sheet, the program provided for causing a computer toexecute setting of the type of the sheet held in the holder on the basisof the basis weight measured by the measurer, the type discriminationtable prescribing a unique range being a range of basis weight in whichthe sheet type is uniquely discriminated, and selection range being arange of basis weight in which the sheet type is discriminated intoeither of a first type in which the basis w eight is relatively largeand a second type in which the basis weight is relatively small, theprogram being provided for causing the computer to execute displaying aselection screen being a screen that receives operation of selecting thesheet type out of the first and second types in a case where the basisweight measured by the measurer is within the selection range, andreceiving selection through the selection screen, wherein, in a casewhere the selection screen is displayed, the type of the sheet held inthe holder is set to the type for which selection has been receivedthrough the selection screen.